Flame candles are often utilized for symbolic religious reasons such as votive candles used in church vestibules and menorahs used on Hannukah. Flame candles are also used for decorative purposes such as in restaurants and for the subdued ambient lighting they provide. Another common use is as a memorial symbol such as at a gravesite. Electronic candles have been accordingly been developed In order to provide a steadier and more reliable light (often at a lower cost) and to minimize dangers associated with open flames, especially when used in large numbers (e.g. extensive votive candle displays) and in public settings. These electronic candles have no open flames and they include special bulbs or LEDs and/or circuitry to enable them to very closely simulate the appearance of a flame candle and the random flicker thereof. In addition, even the largest flame candles have a finite life-time, rarely exceeding a week and longer periods are often desired and only possible with electrically powered lights.
Electronic candles also have secular utility such as decorative lighting in gardens and it is desirable that they be capable of extended lighting duration with minimized battery replacement requirements
For extensive and reliable operation, electronic candles have generally been powered by AC current, either directly or with an AC/DC transformer-rectifier, depending on the utilized bulb parameters. Such candles, connected to a constant current supply, are accordingly capable of being left unattended and remaining indefinitely lit for extended periods of time. Attached timer circuitry provides timer control for selective lighting times.
Alternatively, and less commonly, such candles are powered by direct DC battery current with the batteries contained in a separate supporting base. Such candles are however not generally utilizable as integrally complete units without such base. Additionally, battery powered candles are limited by the available battery capacity and have usable lifetimes often comparable only to that of flame candles. Some completely contained electronic candles have been developed for areas not accessible by electric current lines such as cemeteries but they have been simply lighting fixtures and not true candle emulations.